The Controlled Exposure Facility (CEF) Core provides expertise and facilities to conduct human and animal exposure studies. The Core is comprised of two technology units overseeing exposure chambers that individually provide controlled atmospheres to human subjects or small animals. The controlled environmental chambers share components of the pollutant generation systems, allowing for development of exposure conditions that recapitulate those encountered in both environmental and occupational settings. The goal of the human exposure unit is to provide accurate exposures of human subjects in a setting where many host and environmental factors can be rigorously controlled and where biological specimens can be collected for discovery of biological response indicators and mechanistic studies. The animal exposure unit provides consultation for conducting animal inhalation research in controlled exposure conditions recapitulating those in the human exposure chamber. The ability to generate different atmospheres with known pollutant concentrations in a controlled environment allows testing and calibration of devices that will be used for field and epidemiological studies.